So far, for example, Patent Document 1 discloses a control apparatus for an internal combustion engine that executes learning control for small fuel injection amount. More specifically, this learning control of the small fuel injection amount executes a fuel injection with small amount when a fuel cut operation is performed at the time of deceleration, and is executed based on the relation between the fuel injection amount at this time and a generated torque of the internal combustion engine.
Meanwhile, the following configuration is known as that of a fuel injection valve used for an internal combustion engine. More specifically, a fuel injection valve is known which includes a needle valve that has a seat contact part at its distal end part, and a nozzle body that has a seat part with which the seat contact part comes into contact, and further includes a fuel receiving part (to which, so-called, a sac or the like corresponds) formed downstream of the seat part, and at least one nozzle hole formed downstream of the seat part.
According to the fuel injection valve having the configuration described above, injection characteristics such as injection amount characteristics change whether the valve is in a state in which the fuel amount charged in the fuel receiving part is large (liquid-tight state) or a state in which the amount of fuel charged in the fuel receiving part is small (gas-tight state). Therefore, if the learning control of the small fuel injection amount described in Patent Document 1 is executed in the internal combustion engine including a fuel injection valve having the aforementioned configuration, the fuel injection amount actually injected from the needle holes fluctuates depending on whether the internal state of the fuel receiving part is in the liquid-tight state or the gas-tight state. As a result of this, there is a concern that the accuracy of the learning of fuel injection amount may decrease. In addition, such concern becomes more pronounced when a learning control of small fuel injection amount such as the above described learning control is performed.
Including the above described document, the applicant is aware of the following documents as related art of the present invention.